Customized patient-specific orthopaedic instruments for component placement in a total hip arthroplasty

ABSTRACT

A system for use in conjunction with a hip prosthesis is shown. A customized patient-specific acetabular orthopaedic surgical instrument and a customized patient-specific femoral orthopaedic surgical instrument are disclosed. A method for fabricating and using the orthopaedic surgical instruments is also disclosed. A method for using the customized patient-specific acetabular orthopaedic surgical instrument is disclosed. A method for using the customized patient-specific femoral orthopaedic surgical instrument is disclosed.

This application is a divisional application of U.S. patent Ser. No.14/920,311, now U.S. Pat. No. 10,034,753, filed Oct. 22, 2015, theentirety of which is incorporated by reference.

TECHNICAL FIELD

The present disclosure relates generally to customized patient-specificorthopaedic surgical instruments and more particularly to customizedpatient-specific acetabular orthopaedic surgical instruments andcustomized patient-specific femoral orthopaedic surgical instruments.

BACKGROUND

Joint arthroplasty is a well-known surgical procedure by which adiseased and/or damaged natural joint is replaced by a prosthetic joint.For example, in a hip arthroplasty surgical procedure, a prosthetic hipreplaces a patient's natural hip. A typical prosthetic hip includes anacetabular orthopaedic prosthesis and/or femoral stem orthopaedicprosthesis. A typical acetabular orthopaedic prosthesis includes anacetabular cup, which is secured to the patient's natural acetabulum,and an associated polymer/ceramic/metal bearing or ring. A typicalfemoral orthopaedic prosthesis includes a femoral stem, which is securedto the patient's femur.

To facilitate the replacement of the natural joint with an acetabularorthopaedic prosthesis, orthopaedic surgeons may use a variety oforthopaedic surgical instruments such as, for example, reamers, drillguides, drills, and/or other surgical instruments. Typically, suchorthopaedic surgical instruments are generic with respect to the patientsuch that the same orthopaedic surgical instrument may be used on anumber of different patients during similar orthopaedic surgicalprocedures.

SUMMARY

According to one aspect of the disclosure, a method of using a systemfor facilitating implantation of a hip prosthesis is disclosed. Themethod includes positioning a collar of a customized patient-specificfemoral surgical instrument on a patient's femur bone such that (i) anegative contour defined in a bone-facing surface of the collar receivesa corresponding positive contour of the patient's femur, and (ii) a topsurface of the collar defines a resection plane for resecting thepatient's femur, advancing a resection tool along the resection planesurface of the collar to remove one or more portions of the patient'sfemur, positioning a femoral stem component in the femur bone, andaligning the femoral stem component with an alignment guide coupled tothe collar to position the femoral stem component in a predeterminedposition.

In some embodiments, the method further may include positioning acustomized patient-specific acetabular surgical instrument on apatient's coxal bone such that a negative contour defined in thecustomized patient-specific acetabular surgical instrument receives acorresponding positive contour of the patient's coxal bone, positioningan acetabular cup component in the patient's coxal bone, and aligningthe acetabular cup component with an alignment guide coupled to the bodyto position the acetabular cup component in predetermined position. Insome embodiments, the method further may include determining theposition of the customized patient-specific acetabular surgicalinstrument on the patient's coxal bone using one or more sensors locatedin the customized patient-specific acetabular surgical instrument. Insome embodiments, the method further may include forming an assembledhip joint prosthesis by positioning a femoral head on the femoral stemcomponent and inserting the femoral head into a cavity of the acetabularcup component, and determining the position of the patient's coxal bonerelative to the patient's femur when the assembled hip joint prosthesisis implanted in the patient using one or more sensors positioned in thecustomized patient-specific acetabular surgical instrument and one ormore sensors positioned in the customized patient-specific femoralsurgical instrument. In some embodiments, the method further may includeattaching a reaming guide housing and a reamer to the customizedpatient-specific acetabular surgical instrument, the reamer includingone or more sensors positioned thereon, reaming an acetabular of thepatient to a predetermined depth, and determining how much bone has beenremoved from the acetabulum by comparing the data received from thesensors of the reamer to the data received from the sensors of thecustomized patient-specific acetabular surgical instrument.

In some embodiments, the method further may include determining theposition of the customized patient-specific femoral surgical instrumenton the patient's femur using one or more sensors located in the collar.In some embodiments, the method further may include positioning thealignment guide on the collar of the customized patient-specific femoralsurgical instrument after the patient's femur has been resected by theresection tool. In some embodiments, the method further may includebroaching an intramedullary canal of the patient's femur using a reamingtool.

According to another aspect, an system for facilitating implantation ofa hip prosthesis includes an acetabular cup component and a customizedpatient-specific acetabular surgical instrument. The acetabular cupcomponent defining a cup axis extending away from the acetabular cupcomponent. The customized patient-specific acetabular surgicalinstrument includes a body and an alignment guide. The body having (i)an inner surface defining a cylindrical passageway configured to receivethe acetabular cup component, and (ii) a bone-facing surface having acustomized patient-specific negative contour configured to receive acorresponding positive counter of the patient's coxal bone. Thealignment guide coupled to the body, the alignment guide defining analignment axis positioned to indicate a predetermined position of theacetabular cup component in the patient's coxal bone. In someembodiments, the alignment axis of the alignment guide is positionedaccording to a predetermined version angle and a predeterminedinclination angle of the acetabular cup prosthesis.

In some embodiments, the acetabular cup component includes a base and abody extending away from the base, and the cup axis extends away fromthe acetabular cup component perpendicular to the base. In someembodiments, the customized patient-specific acetabular surgicalinstrument includes one or more sensors configured to determine aposition of the customized patient-specific acetabular surgicalinstrument relative to the coxal bone, wherein each of the one or moresensors are positioned in the customized patient-specific acetabularsurgical instrument based on a predetermined sensor position. In someembodiments, the one or more sensors cooperate with other sensorspositioned on one or more surgical instruments and are configured todetermine the position and orientation of the one or more surgicalinstruments relative to the position and orientation to the patient'sfemur. In some embodiments, the one or more sensors are configured todetermine the position and an orientation of the customizedpatient-specific acetabular surgical instrument relative to a customizedpatient-specific femoral surgical instrument positioned on a patient'sfemur, wherein the customized patient-specific femoral surgicalinstrument includes one or more additional sensors configured tointeract with the one or more sensors of the customized patient-specificacetabular surgical instrument.

In some embodiments, the system further may include a femoral stemcomponent and a customized patient-specific femoral surgical instrument.The femoral stem component defining a trunnion axis extending along atrunnion and a neck of the femoral stem component. The customizedpatient-specific femoral surgical instrument including a collar and analignment guide. The collar sized to fit around a neck of the patient'sfemur, the collar having: (i) a bone-facing surface having a customizedpatient-specific negative contour configured to receive a correspondingpositive counter of the patient's femur, and (ii) top surface defining aresection plane surface configured to guide a surgical instrument as thepatient's femur is resected. The alignment guide coupled to the collar,the alignment guide defining a femoral alignment axis positioned toindicate a predetermined angle of the femoral stem component. In someembodiments, the alignment guide of the customized patient-specificfemoral surgical instrument is positioned to indicate a predeterminedoffset of the femoral stem component.

According to another aspect, a system for facilitating implantation of ahip prosthesis includes a femoral stem component and a customizedpatient-specific femoral surgical instrument. The femoral stem componentdefining a trunnion axis extending along a trunnion and a neck of thefemoral stem component. The customized patient-specific femoral surgicalinstrument includes a collar and an alignment guide. The collar sized tofit around a neck of the patient's femur, the collar having: (i) abone-facing surface having a customized patient-specific negativecontour configured to receive a corresponding positive counter of thepatient's femur, and (ii) top surface defining a resection plane surfaceconfigured to guide a surgical instrument as the patient's femur isresected. The alignment guide coupled to the collar, the alignment guidedefining a femoral alignment axis positioned to indicate a predeterminedangle of the femoral stem component.

In some embodiments, the collar comprises a first collar segment and asecond collar segment connected by a hinge, the hinge defining a hingeaxis, and wherein the first collar segment and the second collar segmentare configured to rotate about the hinge axis to allow the customizedpatient-specific femoral surgical instrument to advance onto thepatient's femur. In some embodiments, the alignment axis of thealignment guide indicates a predetermined offset of the femoral stemcomponent from the patient's femur and indicates a predetermined angleof the femoral stem component relative to the patient's femur.

In some embodiments, the customized patient-specific femoral surgicalinstrument includes one or more sensors. The one or more sensorspositioned in the collar and configured to determine a position of thecustomized patient-specific femoral surgical instrument relative to thepatient's femur, where the one or more sensors are positioned in thecustomized patient-specific femoral surgical instrument based on apredetermined sensor position.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the following figures,in which:

FIG. 1 is a perspective view of an embodiment of a surgical system andan embodiment of a hip joint prosthesis installed in the body of apatient;

FIG. 2 is a perspective view of an embodiment of a customizedpatient-specific acetabular surgical instrument;

FIG. 3 is a perspective view of an embodiment of a customizedpatient-specific femoral surgical instrument;

FIG. 4 is a top plan view of the acetabular surgical instrument of FIG.2;

FIG. 5 is an exploded perspective view of the customizedpatient-specific acetabular surgical instrument of FIG. 2 positioned ona coxal bone;

FIG. 6 is an exploded perspective view of the customizedpatient-specific acetabular surgical instrument of FIG. 2 and a guidehousing;

FIG. 7 is a sectional view of the customized patient-specific acetabularsurgical instrument of FIG. 2, the housing and a reamer taken along theline 7-7;

FIG. 8 is a sectional view of the customized patient-specific acetabularsurgical instrument of FIG. 2 with an alignment guide taken along theline 7-7;

FIG. 9 is a simplified flow diagram of a method of performing anorthopaedic surgical procedure using the acetabular surgical instrumentof FIG. 2;

FIG. 10 is a perspective view of the customized patient-specific femoralsurgical instrument of FIG. 3 secured to a proximal end of a femur of apatient;

FIG. 11 is a side elevation view of a collar segment of the customizedpatient-specific femoral surgical instrument of FIG. 3;

FIG. 12 is a perspective view of the customized patient-specific femoralsurgical instrument of FIG. 3 in an opened position;

FIG. 13 is an exploded perspective view of the customizedpatient-specific femoral surgical instrument of FIG. 3;

FIG. 14 is a perspective view of the customized patient-specific femoralsurgical instrument of FIG. 3 with a portion of the femur resected;

FIG. 15 is a side elevation view of the customized patient-specificfemoral surgical instrument of FIG. 3 secured to the femur of a patientand a femoral stem component positioned in the femur;

FIG. 16 is a simplified flow diagram of a method of performing anorthopaedic surgical procedure suing the femoral surgical instrument ofFIG. 3;

FIG. 17 is a perspective view of an assembled hip joint prosthesis withthe customized patient-specific acetabular surgical instrument of FIG. 2secured to the coxal bone of the patient and the customizedpatient-specific femoral surgical instrument of FIG. 3 secured to thefemur bone of the patient;

FIG. 18 is an exploded perspective view of another embodiment of acustomized patient-specific acetabular surgical instrument;

FIG. 19 is an exploded perspective view of another embodiment of acustomized patient-specific femoral surgical instrument;

FIG. 20 is a perspective view of another embodiment of a customizedpatient-specific acetabular surgical instrument; and

FIG. 21 is a simplified flow diagram of a method for designing andfabricating a customized patient-specific orthopaedic surgicalinstrument.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

References in the specification to “one embodiment”, “an embodiment”,“an example embodiment”, etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to effect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

Referring to FIG. 1, a surgical instrument system 10 used in conjunctionwith a hip joint prosthesis 12 is shown. The surgical instrument system10 includes a customized patient-specific acetabular surgical instrument60 (hereinafter “acetabular surgical instrument 60”) and a customizedpatient specific femoral surgical instrument 300 (hereinafter “femoralsurgical instrument 300”). The hip joint prosthesis 12 includes anacetabular cup 14, a femoral stem 16, and a femoral head 18. Theacetabular cup 14 is configured to be positioned in the patient'ssurgically-prepared acetabulum of the coxal bone 136. The femoral stem16 is configured to be implanted in the patient's surgically-preparedfemur 304. When the hip joint prosthesis is assembled 12, the femoralhead 18 is configured to be positioned on a trunnion of the femoral stem16 and inserted into a cavity formed in the acetabular cup 14.

As shown in FIG. 2, the acetabular surgical instrument 60 includes abody 62 having a customized patient-specific negative contour 66 and oneor more sensors 134 positioned on the body 62. In the illustrativeembodiment, the acetabular surgical instrument 60 includes one or morearms 70, each of the arms 70 having a customized patient-specificnegative contour 86. In other embodiments, the acetabular surgicalinstrument 60 does not include a plurality of arms 70. The acetabularsurgical instrument 60 is configured to couple to the bony anatomy ofthe patient's coxal bone 136. Once coupled to the coxal bone 136, one ormore surgical instruments may be attached to the acetabular surgicalinstrument 60 to assist the surgeon with the orthopaedic surgicaloperation. For example, a reamer 120 or a customized patient-specificalignment guide 122 may be attached to the acetabular surgicalinstrument 60. The alignment guide 122 of the acetabular surgicalinstrument 60 is configured to assist the surgeon in positioning theacetabular cup 14.

As shown in FIG. 3, the femoral surgical instrument 300 includes acollar 302 having a customized patient-specific negative contour 322, acustomized patient-specific alignment guide 360, and one or more sensors384 positioned on the collar 302. The femoral surgical instrument 300also includes a top surface 306 that defines a resection plane 315. Thefemoral surgical instrument 300 is configured to the bony anatomy of thepatient's femur bone 304. Once coupled to the bone, the alignment guide360 of the femoral surgical instrument 300 assists the surgeon inresecting the patient's femur bone 304 and positioning the femoral stem16.

Each of the sensors 134, 384 are positioned in predetermined sensorlocations in their respective surgical instruments 60, 300. Based on thepredetermined sensor locations in the customized patient-specificsurgical instruments 60, 300, the sensors 134, 384 are configured toprovide a bone-coordinate reference frame for the patient's coxal bone136 and the patient's femur 304 during an orthopaedic surgicalprocedure. Using the sensors 134, 384, the surgeon may determine theposition of the femur 304 relative to the coxal bone 136. Based on thisrelative bone position information, a surgeon may be able to determinewhat range of motion and what kinematics a patient will likelyexperience after the orthopaedic surgery is complete. Additionally,other sensors may be positioned in orthopaedic components and otherorthopaedic surgical instruments used during the orthopaedic surgicalprocedure. Using the sensors 134, 384 and these other sensors, thesurgeon may determine the positions and orientations of the orthopaediccomponents and/or the other orthopaedic surgical instruments relative tothe patient's bones 136, 304.

The illustrative embodiment of FIG. 1 shows the surgical instruments 60,300 including alignment guides 122, 360 and sensors 134, 384. In someembodiments, the surgical instruments 60, 300 include the sensors 134,384, but not the alignment guides 122, 360.

Referring now to FIGS. 2 and 3, the pair of customized patient-specificorthopaedic surgical instruments of the surgical instrument system 10cooperate to assist an orthopaedic surgeon to position orthopaedic hipcomponents in a patient during an orthopaedic surgical operation,including implanting an orthopedic hip prosthesis in the patient.Specifically, the acetabular surgical instrument 60 is configured toassist the orthopaedic surgeon to position orthopaedic acetabularcomponents 126 in a patient, and the femoral surgical instrument 300 isconfigured to assist the orthopaedic surgeon to position orthopaedicfemoral stem components 362 in a patient. Furthermore, the pair ofsurgical instruments 60, 300 cooperate to verify the final position andorientation of the assembled orthopaedic hip prosthesis 386 in thepatient as shown in FIG. 17.

In one particular embodiment, the surgical instruments 60, 300 areformed from a polymer or metal produced by additive manufacturing. Inother embodiments, the surgical instruments 60, 300 are formed frominjection-molded, clear polypropylene or other transparent material suchthat the interior of the surgical instruments 60, 300 are visible whenthe surgical instruments 60, 300 are secured to the patient's bonyanatomy. In other embodiments, the surgical instruments 60, 300 may beformed from implant-grade metallic material such as titanium or cobaltchromium. Additionally, the surgical instruments 60, 300 may includeimage intensifiers such as, for example, stainless steel, tantalum, orother dense material to aid in positioning and to check the accuracy ofalignment. For example, the surgical instruments 60, 300 may beconfigured to be radio-opaque and to provide markers in x-ray imagestaken of the patient.

Referring now to FIGS. 2 and 4-8, the acetabular surgical instrument 60includes a guide body 62 configured to contact a portion of thepatient's coxal bone 136 during use. In the illustrative embodiment, theguide body 62 has a generally ring shape but in other embodiments theguide body 62 could have a generally square shape, rectangular shape, orany other suitable form. As best seen in FIG. 7, the body 62 includes abottom surface 64, which is configured to contact a portion of the areaof the patient's coxal bone 136 proximate to the acetabulum. In theillustrative embodiment, the bottom surface 64 includes a customizedpatient-specific negative contour 66 configured to receive thecorresponding positive contour of the acetabular margin 68 of thepatient's coxal bone 136. It should be appreciated that in otherembodiments the bottom surface 64 may include other customizedpatient-specific negative contours that are configured to receive othercorresponding contours of the patient's coxal bone 136 proximate to theacetabulum.

The illustrative acetabular surgical instrument 60 also includes aplurality of arms 70 extending outwardly from the body 62. In otherembodiments, the acetabular surgical instrument 60 does not include aplurality of arms 70. In the illustrative embodiment of FIG. 2, the body62 and the arms 70 are formed as a single monolithic component. However,it should be appreciated that in other embodiments the body 62 and thearms 70 could each be formed from separate pieces. For example, the arms70 may be separately secured to the body 62 via suitable fasteners suchas screws, bolts, adhesive, or the like.

In the illustrative embodiment, the acetabular surgical instrument 60includes three arms 70 extending from the body 62. In other embodiments,the acetabular surgical instrument 60 may include additional or fewerarms depending on the patient's bony anatomy and the preference of thesurgeon. When viewed from the top plan view of FIG. 4, the arms 70extend from the body 62 in a configuration that defines an angle betweeneach arm 70. For example, as illustrated in FIG. 4, an arm 72 and an arm74 define an angle 76 therebetween, the arm 74 and an arm 78 define anangle 80 therebetween, and the arm 72 and the arm 78 define an angle 82therebetween. The magnitude of each of the angles 76, 80, 82 is equal toapproximately 120 degrees. In one particular embodiment, the arms 70 mayextend from the body 62 such that the each of the angles 76, 80, 82 hasa magnitude different from any other angle. Like many other dimensionalcharacteristics described herein, the magnitude of the angles 76, 80, 82may be customized to as required for the particular patient.

Each arm 70 is configured to contact a portion of the patient's coxalbone 136 during use. Each arm 70 includes a bottom surface 84 that isconfigured to contact a portion of the area of the patient's coxal bone136 proximate to the acetabulum. Each bottom surface 84 includes acustomized patient-specific negative contour 86 configured to receive aportion of the corresponding contour of the patient's coxal bone 136proximate to the acetabulum. In some embodiments, the arm 72 has acustomized patient-specific negative contour 86 configured to receivethe corresponding positive contour of the ilium of the patient's coxalbone 136. It should be appreciated that in other embodiments, the bottomsurface 84 may include other customized patient-specific negativecontours that are configured to receive other corresponding contours ofthe patient's coxal bone 136 proximate to the acetabulum. For example,the bottom surface 84 of another arm 70 may include a customizedpatient-specific negative contour configured to receive a correspondingcontour of the pubis or the ischium of the patient's coxal bone 136. Thenegative contours 66, 86 include ridges 138 and depressions 140 that areconfigured to match corresponding the depressions and ridges of thepatient's bony anatomy. The negative contours 66, 86 cooperate to ensurethe acetabular surgical instrument 60 is placed on the patient's coxalbone 136 in a desired position and orientation, which is based on thepredetermined inclination plane and the predetermined version plane ofthe acetabular orthopaedic prosthesis.

Each arm 70 includes a top surface 96 positioned opposite the bottomsurface 84. Each arm 70 also includes an inner surface 98 that defines apassageway 100 extending through each arm 70. Each passageway 100 issized to receive a corresponding bone pin 102 to be secured to thepatient's coxal bone 136 as shown in FIG. 5. The bone pins 102 cooperateto lock the acetabular surgical instrument 60 in the unique position andorientation. It should be appreciated that in other embodiments thepassageway 100 may be sized to receive wire or other retaining devicessuitable for locking the acetabular surgical instrument 60 into place onthe coxal bone 136.

As shown in FIG. 2, each passageway 100 is angled relative to the topsurface 96 and the bottom surface 84. Each passageway 100 has a diameter104 that is slightly larger than the outer diameter of the bone pin 102,and the passageway 100 of each arm 70 has a substantially circularcross-section. It should be appreciated that in other embodiments eacharm 70 may include a passageway 100 configured to receive a bone pinwith a different cross-sectional shape. It will also be appreciated thatthe passageway 100 may have any cross-sectional shape suitable forreceiving a drill bit of a bone drill and passing a bone pintherethrough.

The guide body 62 includes a top surface 110 positioned opposite thebottom surface 64. An inner surface 112 connects the top surface 110 tothe bottom surface 64 and defines an illustratively cylindricalpassageway 114 extending therebetween. The guide body 62 also includesan outer surface 116 positioned opposite the inner surface 112. In someembodiments, the top surface 110 may be used to align the acetabular cupcomponent 126 in the patient's coxal bone 136.

In the illustrative embodiment, the passageway 114 of the body 62defines a longitudinal axis 118 that is oriented relative to the bottomsurface 64 of the body 62 based on the predetermined version angle andthe predetermined inclination angle of the acetabular cup prosthesis. Asshown in FIGS. 2 and 7, the axis 118 extends generally perpendicular tothe bottom surface 64. In other embodiments, the axis 118 may be angledin one or more directions relative to the bottom surface 64 depending onthe predetermined inclination and version angles for the particularpatient. As will be discussed in greater detail below, an acetabularreamer 120 is limited to movement along the axis 118 while being used toshape the patient's acetabulum. In that way, the acetabular surgicalinstrument 60 ensures that the patient's acetabulum is shaped to receivethe acetabular cup prosthesis 126 according to the predeterminedinclination and version angles.

The acetabular surgical instrument 60 also includes an alignment guide122 coupled to the guide body 62 as shown in FIGS. 2 and 8. Thealignment guide 122 is configured to assist the orthopaedic surgeon inplacing the orthopaedic acetabular components 126, such as an acetabularcup prosthesis or trialing component. The alignment guide 122 extendsgenerally parallel to the axis 118 away from the top surface 110 of theacetabular surgical instrument 60 to provide a visual indicator of theplanned position and orientation of the orthopaedic prosthesis. As partof the fabrication process of the customized patient-specific acetabularsurgical instrument 60, the position and orientation of the alignmentguide 122 is determined based on the planned position and orientation ofthe acetabular cup prosthesis 126, such as a predetermined version angleand the predetermined inclination. Using those predetermined values, thealignment guide 122 is designed to provide a visual reference for theorthopaedic surgeon when implanting the orthopaedic acetabularcomponents 126.

The alignment guide 122 is configured to be removably coupled toacetabular surgical instrument 60. In this way, the alignment guide 122can be removed to allow other surgical instruments to be attached to theacetabular surgical instrument 60, such as the reamer 120.

The alignment guide 122 is configured to cooperate with a surgical tool124 to provide a visual indication of the position and orientation ofthe orthopaedic acetabular components 126. To accomplish this, thealignment guide 122 defines an alignment axis 128. The alignment axis128 is oriented parallel to the alignment guide 122. In the illustrativeembodiment of FIG. 8, the alignment axis 128 extends parallel to thelongitudinal axis 118. In such an embodiment, the alignment axis 128extends perpendicular relative to the bottom surface 64 of the body 62based on the predetermined version angle and the predeterminedinclination angle of the acetabular cup prosthesis 126. In otherembodiments, the alignment axis 128 may be angled in one or moredirections relative to the bottom surface 64 according to thepredetermined inclination and version angles.

As shown in FIG. 8, the position and orientation of the acetabular cupcomponent 126 may be compared to a predetermined position andorientation using the alignment guide 122. The acetabular cup component126 includes a base 142 and sidewall 143. The sidewall 143 extends awayfrom the base 142 and terminates in an apex 144. The base 142 and thesidewall 143 define a cavity 145 sized to receive the femoral head 18 ofthe hip joint prosthesis 12. The acetabular cup component 126 alsodefines a cup axis 130. The cup axis 130 extends outwardly from the apex144 perpendicularly to the base 142. In the illustrative embodiment ofFIG. 8, the cup axis 130 extends along the shaft of the surgical tool124, where the surgical tool 124 is coupled to the acetabular cupcomponent 126. In the illustrative embodiment, the acetabular cupcomponent 126 is an acetabular cup prosthesis. In other embodiments, theacetabular cup component 126 may be a trialing component.

In some embodiments, the acetabular cup component 126, such as atrialing component, includes one or more sensors (not shown). The one ormore sensors of the acetabular cup component 126 are configured tocooperate with the sensors 134 of the acetabular surgical instrument 60.The sensors of the acetabular cup component 126 and the sensors 134 ofthe acetabular surgical instrument 60 may be configured to cooperate todetermine the position of the acetabular cup component 126 relative tothe patient's coxal bone 136. In other embodiments, other acetabularcomponents, such as the acetabular cup prosthesis, include one or moresensors that cooperate with the sensors 134 to determine the positionand orientation of the acetabular components relative to the patient'scoxal bone 136.

To position the acetabular cup component 126 in the predeterminedposition and orientation, the cup axis 130 should be aligned with thealignment axis 128. An orthopaedic surgeon is able to align these twoaxes 128, 130 by comparing the alignment guide 122 to the surgical tool124. In such a manner, an orthopaedic surgeon is able tointraoperatively determine if the acetabular cup component 126 ispositioned and oriented in the predetermined position and orientation.In some embodiments, the alignment guide 122 may include markings madeon one or more of its surfaces to further provide visual indications ofthe predetermined position and orientation of the acetabular cupprosthesis 126.

As discussed above, the acetabular surgical instrument 60 also includesone or more sensors 134 positioned in the body 62 of the acetabularsurgical instrument 60. The one or more sensors 134 are configured toindicate the location of the acetabular surgical instrument 60 to acomputing device such as the computing device shown and described inU.S. Pat. No. 8,265,949, which is expressly incorporated herein byreference. The sensors 134 are positioned in the customizedpatient-specific acetabular surgical instrument 60 in specific locationsbased on the predetermined position and orientation of the acetabularcup prosthesis 126. The sensors 134 are configured to measure therelative orientation and position of the acetabular surgical instrument60 to one or more other sensors positioned elsewhere. For example, thesensors 134 may cooperate with sensors 384 positioned in a customizedpatient-specific femoral surgical instrument 300 to determine theposition of the acetabular surgical instrument 60 relative to thefemoral surgical instrument 300. The sensors 134 may also be configuredto provide a bone-coordinate reference frame that indicates the positionand orientation of the patient's coxal bone 136. In illustrativeembodiments, the sensors 134 cooperate with other sensors (e.g., sensors384 of the femoral surgical instrument 300) to determine the position ofthe coxal bone 136 relative to the position of the femur 304. Thesensors 134 may also be configured to cooperate with sensors positionedon other surgical instruments (e.g., reamer) or other orthopaediccomponents (e.g., trialing components) to validate the use of suchequipment during an orthopaedic surgical procedure.

The one or more sensors 134 may be embodied as electromagnetic trackingdevices. Each electromagnetic tracking device cooperates with atransmitter and uses orthogonal magnetic fields to determine theposition and orientation of the tracking device. The transmitterincludes three orthogonal coils that are pulsed in a sequence to producean electromagnetic field. Each electromagnetic tracking device alsoincludes three orthogonal coils configured to measure theelectromagnetic field produced by the transmitter. A computing devicedetermines the position and orientation of the electromagnetic trackingdevice by comparing the strength of the received signals to theelectromagnetic field that was produced by the transmitter. In someembodiments, the computing device is positioned on the electromagnetictracking device. In other embodiments, the computing device isindependent from the electromagnetic tracking device.

In some embodiments, the one or more sensors 134 may be embodied asanother type of position and orientation sensor, such as anaccelerometer. In other embodiments, the one or more sensors 134 may beembodied as inertial measurement units (IMU) configured to determine theposition and orientation of the sensors 134 using a combination ofsensors (e.g., accelerometers, gyroscopes, and/or magnetometers).

In some embodiments, the sensors 134 may be embodied as a passivetransponder, such as a radio-frequency identification (RFID) tag. Insuch an embodiment, an RFID reader transmits an RF signal, which powersthe sensor 134, and causes the sensor 134 to transmit information backto the RFID reader via another RF signal. If an RFID tag is interrogatedby multiple RFID readers, a process of triangulation may be used todetermine the precise location of the RFID tag. The RFID readers areconnected to a computing device, which processes the data received fromthe sensors 134 to determine the position of the acetabular surgicalinstrument 60.

In yet other embodiments, the one or more sensors 134 of the acetabularsurgical instrument 60 may include more than one type of sensor on thesame acetabular surgical instrument. For example, the acetabularsurgical instrument 60 may include both an electromagnetic trackingdevice and an RFID tag.

The acetabular surgical instrument 60 may be configured to prepare thepatient's acetabulum to receive an acetabular cup prosthesis 126. Asshown in FIGS. 6 and 7, a housing 150 is configured to be secured to theguide body 62 of the acetabular surgical instrument 60. The housing 150and the reamer 120 are just one example of the surgical tools that maybe coupled to the acetabular surgical instrument 60. In otherembodiments, other types of tool may be coupled to the acetabularsurgical instrument 60.

The housing 150 has a cylindrical main body 152 extending from an upperend 154 to a lower end 156. A sleeve 158 extends outwardly from thelower end 156 and includes an outer surface 160. The outer surface 160has a diameter 162 that is less than a diameter 164 of the passageway114 of the guide body 62. When the housing 150 is secured to theacetabular surgical instrument 60, the sleeve 158 is positioned in thepassageway 114. As shown in FIG. 7, the passageway 114 is sized suchthat the acetabular reamer 120 may be moved through the passageway 114and placed into contact with the patient's acetabulum. The acetabularreamer 120 includes a reamer head 166 removably secured to a reamershank 168. The diameter 164 of the cylindrical passageway 114 is largerthan an outer diameter 170 of the reamer head 166 to allow the reamerhead 166 to advance therethrough. One example of an illustrativeacetabular reamer surgical tool useable with the acetabular surgicalinstrument 60 is the DePuy Quickset® Acetabular Grater System, which iscommercially available from DePuy Synthes Products, Inc. of Warsaw, Ind.U.S.A.

The sleeve 158 includes a pair of flanges 172 projecting outwardly fromthe outer surface 160 of the sleeve 158 as shown in FIG. 6. The flanges172 are spaced apart from the lower end 156 of the main body 152 andextend in an arc about the circumference of the sleeve 158.

The guide body 62 includes a pair of corresponding slots 174 definedtherein that are configured to receive the flanges 172 as best shown inFIG. 2. Each slot 174 includes a notch 176 extending from an upper end178 defined in the top surface 110 of the body 62 to a lower end 180defined in the inner surface 112 of the body 62. Each slot 174 alsoincludes a channel 182 defined in the inner surface 112 that extendsfrom the lower end 180 of the notch 176 to a distal end 184. The lengthof the channel 182 substantially corresponds to the length of the flange172. The channel 182 extends orthogonally to the longitudinal axis 118.However, in other embodiments the channel 182 may be tilted relative tothe longitudinal axis 118 depending the desired position and orientationof the acetabular surgical instrument 60.

The slots 174 and the flanges 172 cooperate to secure the housing 150 tothe acetabular surgical instrument 60. The housing 150 is aligned withthe acetabular surgical instrument 60 such that each flange 172 ispositioned to be received into a notch 176 of a corresponding slot 174.When the housing 150 is seated on the acetabular surgical instrument 60,a bottom 185 of each flange 172 contacts the lower end 180 of the notch176. The housing 150 is then rotated about the longitudinal axis 118 toadvance each flange 172 into the channel 182 of the corresponding slot174 until an end of the flange 172 is placed in contact with the distalend 184 of the channel 182. In such a manner, the housing 150 is securedto the acetabular surgical instrument 60.

In other embodiments, the acetabular surgical instrument 60 and thehousing 150 include a different number of flanges 172 and slots 174. Inother embodiments, the housing 150 may be securable to the acetabularsurgical instrument 60 by other methods. For example, the sleeve 158 mayhave an external thread and the body 62 may have a correspondinginternal thread. In such embodiments, the sleeve 158 may be threadedonto the body 62. In other embodiments, the housing 150 may include alatching mechanism secured to the main body 152 that engages with thebody 62. Similarly, the housing 150 may be secured to the body 62 viasuitable fasteners such as screws, bolts, or the like. In otherembodiments, the acetabular surgical instrument 60 is not configured tocouple to the housing 150, and therefore does not include any slots 174formed in the body 62 thereof.

As best shown in FIG. 7, the sleeve 158 includes an inner surface 186that defines a lower passageway 188. The lower passageway 188 has adiameter 190 that is slightly larger than the outer diameter 170 of thereamer head 166 of the acetabular reamer 120. As such, the lowerpassageway 188 is sized such that the acetabular reamer 120 may be movedalong the longitudinal axis 118 and placed into contact with thepatient's acetabulum. The main body 152 includes an inner surface 192that defines a central passageway 194 connected with the lowerpassageway 188. The central passageway 194 has a diameter 196 that islarger than the diameter 190 of the lower passageway 188. However, inother embodiments, the diameter 196 of the central passageway 194 may besubstantially equal to the diameter 190 of the lower passageway 188.

A hollow shaft 198 extends upwardly from the upper end 154 of the mainbody 152. The shaft 198 includes an inner surface 200 that defines acylindrical passageway 202 extending from a top end 204 of the shaft 198to the upper end 154 of the main body 152. As shown in FIG. 7, thecylindrical passageway 202 is fluidly connected with the centralpassageway 194 of the main body 152. The cylindrical passageway 202 hasan inner diameter 210 that is smaller than the diameters 190, 196 of thepassageways 188, 194 and that is only slightly larger than the outerdiameter 170 of the reamer shank 168 of the acetabular reamer 120.

The acetabular surgical instrument 60, the housing 150, and the reamer120 cooperate to ream the patient's acetabulum to a predetermined depth.The main body 152 and the shaft 198 define a total length 206. Themagnitude of the total length 206 is set based on the predetermineddepth to which the orthopaedic surgeon plans to ream the patient'sacetabulum. The top end 204 of the shaft 198 cooperates with aprotrusion 208 positioned on the reamer shank 168 to ensure that thereamer head 166 does not advance beyond the predetermined depth.

In some embodiments, the reamer 120 includes one or more sensors (notshown) configured to cooperate with the sensors 134 of the acetabularsurgical instrument 60. For example, the sensors of the reamer 120 maybe positioned in the reamer head 166. The sensors of the reamer 120 andthe sensors 134 of the acetabular surgical instrument 60 may cooperateto determine the amount of material the surgeon has reamed from thepatient's coxal bone 136. For example, using the bone-coordinatereference frame established by the sensors 134, the sensors of thereamer 120 may be able to determine the position and orientation of thereamer 120 relative to the coxal bone 136 and how much material has beenremoved from the coxal bone 136 by the reamer 120. In other embodiments,other surgical instruments include one or more sensors that cooperatewith the sensors 134 to validate the operation of those surgicalinstruments during the orthopaedic surgical procedure.

In use, the acetabular surgical instrument 60 is configured to bothassist in preparing a patient's acetabulum for surgery and positioningone or more orthopaedic acetabular components 126 in thesurgically-prepared acetabulum. Referring to FIG. 9, a method 220 forusing the acetabular surgical instrument 60 is shown. The method 220includes step 222 in which an orthopaedic surgeon positions theacetabular surgical instrument 60 on the patient's coxal bone 136. Theacetabular surgical instrument 60 is positioned such that the negativecontours 66, 86 of the acetabular surgical instrument 60 receive aportion of the corresponding contour of the patient's coxal bone 136proximate to the acetabulum. Once the acetabular surgical instrument 60is positioned on the patient's coxal bone 136, the acetabular surgicalinstrument 60 may be secured to the coxal bone 136 using one or morebone pins 102.

In step 224, an orthopaedic surgeon secures the reamer 120 and thehousing 150 to the acetabular surgical instrument 60. The acetabularsurgical instrument 60, the reamer 120, and the housing 150 cooperate todefine a predetermined reaming depth. In step 226, the orthopaedicsurgeon advances the reamer along the longitudinal axis 118 and reamsthe patient's acetabulum to a predetermined depth. Before positioningany orthopaedic acetabular components 126 (e.g., trialing components orprosthesis components), in step 228, the orthopaedic surgeon removes thereamer 120 and the housing 150 from the acetabular surgical instrument60.

In step 230, the orthopaedic surgeon secures the alignment guide 122 tothe acetabular surgical instrument 60. The alignment guide 122 definesan alignment axis 128 and is configured to provide a visual indicationto the orthopaedic surgeon indicative of the predetermined position andpredetermined orientation of the acetabular cup prosthesis 126. As bestshown in FIG. 8, the surgical tool 124 and the alignment guide 122cooperate to provide the visual indication of the predetermined positionand orientation. In step 232, the orthopaedic surgeon positions theacetabular cup component 126 by adjusting the surgical tool 124, whichis coupled to the acetabular cup component 126, until the surgical tool124 is aligned with the alignment guide 122.

Referring now to FIGS. 3 and 10-15, the femoral surgical instrument 300includes a collar 302 configured to contact portions of the patient'sfemur bone 304 during use. In the illustrative embodiment, the collar302 has a generally annular shape. As is best shown in FIG. 10, thecollar 302 is configured to wrap around the neck of the patient's femurbone 304. As best shown in FIG. 3, the collar 302 also includes a topsurface 306, an outside surface 308, a bottom surface 310, a bone-facingsurface 312, and a hinge 314.

The top surface 306 extends outwardly from an inner edge 316 defined bythe bone-facing surface 312 to an outer edge 318 defined by the outsidesurface 308. The top surface 306 defines a resection plane 315 isconfigured to guide an orthopaedic resection tool as a portion of thepatient's femur bone 304 is resected. A femur bone 304 that has beenresected using the femoral surgical instrument 300 is shown in FIG. 14.The resection plane 315 of the top surface 306 is formed based on apredetermined bone resection the orthopaedic surgeon determines duringthe pre-operative planning. While the illustrative embodiment shows atop surface 306 that is planar, in other embodiments, a blade stop maybe formed in the top surface 306. The blade stop may be configured toarrest the movement of a resection tool's blade at a predeterminedposition. In the illustrative embodiment, the resection plane 315 isdefined by the top surface 306, which acts as a non-captured cuttingguide. In other embodiments, the resection plane 315 is defined by acaptured cutting guide. In some embodiments, to protect a femoralsurgical instrument 300 made of a polymer, the top surface 306 may beformed of metal.

In use, an orthopaedic surgeon will position a blade 390 of a resectiontool against the top surface 306. The blade 390 will be oriented so thatthe cut made by the blade 390 will be parallel to the resection plane315. The surgeon will advance the resection tool along the top surface306 removing portions of the patient's femur bone 304. Once all of thedesired portions of the patient's femur bone 304 have been resected, theorthopaedic surgeon will remove the resection tool. In the illustrativeembodiment of FIG. 14, the entire head of the femur bone 304 wasresected. In some embodiments, the femoral surgical instrument 300 maybe used to make a conservative neck cut on the neck of the femur 304 anda taper is applied to remove the femoral head.

As best shown in FIG. 11, the bone-facing surface 312 of the femoralsurgical instrument 300 extends from the inner edge 316 to a bottom edge320 defined at the intersection of the bone-facing surface 312 and thebottom surface 310. The bone-facing surface 312 includes a customizedpatient-specific negative contour 322 configured to receive acorresponding positive contour of the neck of the femur bone 304 andsurrounding regions as shown in FIG. 15. The negative contour 322includes ridges 348 and depressions 350. The ridges 348 correspond todepressions found in the patient's bony anatomy and the depressions 350correspond to ridges found in the patient's bony anatomy. In this way,the negative contours 322 of the bone-facing surface 312 cooperate toensure the femoral surgical instrument 300 is placed on the patient'sfemur bone 304 in a desired position and orientation, which is based onthe predetermined offset 364 and the predetermined angle 365 of thefemoral stem prosthesis. In other embodiments, the bone-facing surface312 may include other customized patient-specific negative contours thatare configured to receive other corresponding contours of the patient'sfemur bone 304 proximate to the neck of the femur 304.

At the inner edge 316, the bone-facing surface 312 defines a top innerdiameter 324 of the collar 302. The top inner diameter 324 is sized toreceive the neck and related portions of the femur bone 304. Since thebone-facing surface 312 conforms to the femur bone 304, the precisedistance of the top inner diameter 324 varies according to the shape ofthe patient's femur bone 304. At the bottom edge 320, the bone-facingsurface 312 also defines a bottom inner diameter 326 of the collar 302.The bottom inner diameter 326 being larger than top inner diameter 324,based on the patient's specific bony anatomy.

The outside surface 308 of the collar 302 extends from the outer edge318 to a lower edge 328 defined at the intersection of the outsidesurface 308 and bottom surface 310. The outside surface 308 defines aheight 330 of the collar 302. The height 330 defines, in part, preciselocation of the resection plane 315 relative to the patient's femur bone304. The outside surface 308 of the collar 302 also defines an outerdiameter 331 of the collar 302. In other embodiments, a height of thecollar 302 may defined as the longitudinal distance between the inneredge 316 and the bottom edge 320. The collar 302 also includes a notch352 formed in an open end 342 of the femoral surgical instrument. Thenotch 352 includes a customized patient-specific negative contour 354having ridges and depressions and configured to receive a positivecontour of the patient's femur bone 304.

In the illustrative embodiment, the collar 302 includes a first collarsegment 332 and a second collar segment 334. The collar segments 332,334 are coupled to one another by the hinge 314 positioned at a hingeend 336 of the collar 302. In other embodiments, the collar 302 does notinclude a hinge, but rather both of the collar segments 332, 334 mayutilize one or more fasteners to secure the collar segments 332, 334 toeach other and to the femur 304. Each collar segment 332, 334 extendsfrom a first contacting surface 338, positioned at the hinge end 336, toa second contacting surface 340, positioned at an open end 342 of thecollar 302. Each collar segment 332, 334 is arcuate in shape. The secondcontacting surface 340 of each collar segment 332, 334 is configured tocontact the other second contacting surface 340 when the first collarsegment 332 and the second collar segment 334 are positioned to form anannular ring.

The hinge 314 interconnects the first collar segment 332 to the secondcollar segment 334 at the hinge end 336 and is configured to allow eachof the collar segments 332, 334 to rotate about a hinge axis 344. Therelative rotation of the collar segments 332, 334 allows the collar 302to rotate between a closed position and an open position. In the closedposition, the second contacting surface 340 of each collar segment 332,334 contacts the other second contacting surface 340 and the collar 302forms an annular ring as shown in FIG. 3. In the open position, thesecond contacting surfaces 340 of the collar segments 332, 334 do notcontact each other, as shown in FIG. 12. In the open position, a gap 346is formed between the collar segments 332, 334 at the open end 342 ofthe collar 302.

To position the collar 302 on the femur bone 304, an orthopaedic surgeonwill rotate one of the collar segments 332, 334 until the gap 346between the collar segments 332, 334 is large enough to allow a portionof the femur bone 304 to pass through. The orthopaedic surgeon will thenadvance the collar 302 onto the femur bone 304 and position the femurbone 304 to be adjacent to the bone-facing surface 312. Once positioned,the surgeon will rotate the collar segments 332, 334 until the collar isin the closed position. In some embodiments, the collar 302 may besecured in the closed position using methods that are known to one ofordinary skill in the art. For example, the collar 302 may include afriction-fit fastener positioned on the second contacting surfaces 340,a hook and latch fastener positioned on the outside surface 308,adhesive may be applied to the second contacting surfaces 340, the hinge314 may be configured to generate resistance to keep the collar 302 inthe closed position, fasteners, such as screws, and/or any other type offastening system.

The femoral surgical instrument 300 also includes a customizedpatient-specific alignment guide 360 removably coupled to the collar 302as shown in FIG. 3. The alignment guide 360 is configured to provide avisual indication to the orthopaedic surgeon about the planned positionand orientation of a femoral stem component 362. In the illustrativeembodiment, the femoral stem component 362 is a femoral stem prosthesisconfigured to be implanted in a patient. In other embodiments, thefemoral stem component may be a femoral trialing component. The positionand orientation of the alignment guide 360 on the femoral surgicalinstrument 300 is customized according to the needs of the patient asdiscussed in greater detail below.

As best shown in FIG. 15, the alignment guide 360 indicates apredetermined offset 364 of the femoral stem component 362 and apredetermined angle 365 of the femoral stem component 362. The femoralstem component 362 includes a body 366, a neck 368 extending superiorlyand medially from the body 366, and a trunnion 370 extending superiorlyand medially from the neck 368. Trunnion 370 is also configured toreceive a femoral head component. The offset 364 is defined as thedistance from the center of rotation of the femoral head component to anaxis 372 running down the center of the patient's femur bone 304. Thepredetermined angle 365 is defined as the angle between a trunnion axis388 and the axis 372.

As shown in FIG. 15, the position and orientation of the femoral stemcomponent 362 may be compared to a predetermined position andorientation using the alignment guide 360. The alignment guide definesan alignment axis 373 extending parallel to the alignment guide 360. Inuse, the alignment axis 373 defined by the alignment guide 360 iscompared to the trunnion axis 388 defined by femoral stem component 362to determine whether the femoral stem component 362 is positioned in thepredetermined position and orientation. If the femoral stem component362 is not positioned according to the predetermined position andorientation, the orthopaedic surgeon may reposition the femoral stemcomponent 362 until the femoral stem component 362 is in the correctposition relative to the alignment guide 360. In some embodiments, thealignment guide 360 includes one or more markings 374 indicative of theplanned position and orientation of the femoral stem component 362.

The alignment guide 360 is configured to be removably coupled to thefemoral surgical instrument 300. In this way, the alignment guide 360can be removed to allow other surgical operations to be performed usingthe femoral surgical instrument 300, such as resecting the femur 304.

As shown in FIG. 13, the alignment guide 360 may be coupled to thefemoral surgical instrument 300 using a system of flanges and slots. Thealignment guide 360 includes two slots 376 that are configured receive apair of corresponding flanges 378 positioned on the outside surface 308of the collar 302. Each slot 376 includes an opening 380 and a lip 382.The opening 380 is sized to receive the flange 378 into the slot 376.The lip 382 extends over a part of the slot 376 and is configured tocooperate with the flange 378 to secure the alignment guide 360 to thecollar 302. Each flange 378 includes a neck extending away from theoutside surface 308 and a top extending away from the outside surface308. The top having a greater diameter than the neck. In use, each slot376 is inserted over a corresponding flange 378. The top passing all theway through the opening 380 of the slot 376 of the alignment guide 360.The alignment guide 360 is then advanced such that the lip 382 engageswith the top and neck of the flange 378. In this manner, the alignmentguide 360 and the collar 302 may be connected in a fixed positionrelative to the one another. In other embodiments, the alignment guide360 may be coupled to the collar 302 using other methods known topersons of ordinary skill in the art.

The femoral surgical instrument 300 also includes one or more sensors384 positioned in the collar 302 configured to indicate the location ofthe femoral surgical instrument 300 to a computing device. The computingdevice is similarly embodied as the computing device described above inrelation to the acetabular surgical instrument 60. The sensors 384 arepositioned in the collar 302 in specific locations based on thepredetermined position and orientation of the femoral stem component362.

The sensors 384 are configured to measure the relative orientationand/or the relative position of the femoral surgical instrument 300 toone or more other sensors positioned elsewhere. For example, the sensors384 may cooperate with sensors 134 positioned in the acetabular surgicalinstrument 60 to determine the position of the femoral surgicalinstrument 300 relative to the acetabular surgical instrument 60. Inother examples, the sensors 384 may cooperate with sensors positioned inother surgical instruments, trialing components, prosthetic components,or robotic surgical tools. In some embodiments, the sensors 384 areconfigured to measure the position and orientation relative to a globalreference frame (such as multiple sensor readers set up to performtriangulation of the sensors 384 position).

As shown in FIG. 17, the acetabular surgical instrument 60 and thefemoral surgical instrument 300 may cooperate to determine if theassembled hip prosthesis 386 is properly positioned in the patient.Using the sensors 134, 384 on the surgical instruments 60, 300, anorthopaedic surgeon is able to determine the relative locations of thecoxal bone 136 and the femur bone 304. With this data, the orthopaedicsurgeon is better able to whether the assembled hip prosthesis 386 ispositioned correctly before finishing the orthopaedic surgicaloperation.

The sensors 384 of the femoral surgical instrument 300 are embodiedsimilarly to the sensors 134 of the acetabular surgical instrument 60described above. The sensors 384 are configured to cooperate with othersensors positioned on the acetabular surgical instrument 60, othersurgical instruments (e.g., a broach), and/or orthopaedic components(e.g., trialing components). The sensors 384 determine a bone-coordinatereference frame for the patient's femur 304. Using this bone-coordinatereference frame, the sensors 384 cooperate with other sensors tovalidate the use of other surgical instruments (e.g., determinebroaching depth) and validate the position and orientation oforthopaedic components relative to the femur 304.

In use, the femoral surgical instrument 300 is configured to both assistin preparing a patient's femur bone 304 for surgery and positioning oneor more femoral stem components 362 in the surgically-prepared femur304. Referring to FIG. 16, a method 400 for using the femoral surgicalinstrument 300 is shown. The method 400 includes step 402 in which theorthopaedic surgeon positions the femoral surgical instrument 300 on thepatient's femur bone 304. The femoral surgical instrument 300 ispositioned such that the negative contours 322 bone-facing surface 312receive a portion of the corresponding positive contour of the patient'sfemur bone 304.

Once the femoral surgical instrument 300 is positioned on the patient'sfemur bone 304, in step 404, the orthopaedic surgeon resects the femur304 using the top surface 306 as a resection guide. As best seen in FIG.14, the collar 302 may define a resection plane 315 to remove the headof the patient's femur bone 304.

After the femur 304 has been resected and surgically-prepared, in step406, the orthopaedic surgeon positions the alignment guide 360 on thecollar 302 of the femoral surgical instrument 300. In step 408, theorthopaedic surgeon then positions the femoral stem component 362 asshown in FIG. 15. The orthopaedic surgeon uses the alignment guide 360as a visual guide to assist in the placement of the femoral stemcomponent 362.

Referring to FIG. 17, the surgical instrument system 10 may be used toverify the position of the patient's coxal bone 136 and the patient'sfemur bone 304 when an assembled hip prosthesis 386 has been implantedin the patient's body. The sensor(s) 134 of the acetabular surgicalinstrument 60 and the sensor(s) 384 of the femoral surgical instrument300 are configured to provide position data indicative of the positionof the coxal bone 136 and the femur bone 304 to the computing devicedescribed above. By comparing the position and orientation data for eachof the surgical instruments 60, 300, an orthopaedic surgeon maydetermine whether the assembled hip prosthesis 386 is positionedcorrectly. In particular, by knowing the positions of the coxal bone 136and the femur bone 304, the orthopaedic surgeon may determine what theoffset, the leg length, and the range of motion of the patient will beafter the orthopaedic surgical operation is complete.

Referring to FIG. 18, a modular customized patient-specific acetabularsurgical instrument 420 is shown. The acetabular surgical instrument 420includes a low-profile block 422 and an upper ring 424. The low-profileblock 422 includes a bottom surface 426, one or more arms 428, and a topsurface 436. Both the bottom surface 426 and the arms 428 have negativecontours 430 configured to receive a positive contour of the patient'scoxal bone 136. In some embodiments, the top surface 436 is configuredto assist the surgeon in positioning the acetabular cup component 126 ina predetermined position and orientation. The low-profile block 422 alsoincludes one or more sensors 434. The sensors 434 are embodied similarlyto the other sensors described above 134, 384.

In the illustrative embodiment, the upper ring 424 includes attachmentfeatures 432. The attachment features 432 are configured to allow othersurgical tools (e.g., reamer 120 and housing 150) to couple to theacetabular surgical instrument 420. In some embodiments, an alignmentguide 122 may be coupled to the upper ring 424.

In use, the upper ring 424 is detached from the low-profile block 422before the hip prosthesis is assembled. The smaller size (e.g., thesmaller height) of the low-profile block 422 is configured to minimizeany interference between the assembled hip prosthesis and the acetabularsurgical instrument 420. The sensors 434 of the low-profile block 422are configured to determine the position of the acetabular surgicalinstrument 420 relative to other features, such as, for example, sensorson a femoral surgical instrument. In other embodiments, the low-profileblock 422 only includes a small portion of the acetabular surgicalinstrument 420. For example, the low-profile block 422 may only includeone of the arms 428 and the one or more sensors 434.

Referring to FIG. 19, a customized patient-specific femoral surgicalinstrument 450 is shown. The femoral surgical instrument 450 includes alow-profile block 452 and an upper ring 454. Both the low-profile block452 and the upper ring 454 include a bone-facing surface 456 having anegative contour and configured to receive a positive contour of thepatient's femur bone 304. The upper ring 454 includes a top surface 458that defines a resection plane 460. The upper ring 454 may be used as aresection guide to a surgical resection tool during an orthopaedicprocedure. The upper ring 454 is detachable from the low-profile block452. The low-profile block 452 includes one or more sensors 462configured to determine the position of the femoral surgical instrument450.

In use, the upper ring 454 is detached from the low-profile block 452before the hip prosthesis is assembled. The smaller size (e.g., thesmaller height) of the low-profile block 452 is configured to minimizeany interference between the assembled hip prosthesis and the femoralsurgical instrument 450. The sensors 462 of the low-profile block 452are configured determine the position of the femoral surgical instrument450 relative to other features, such as, for example, sensors on aacetabular surgical instrument. The sensors 462 are embodied similarlyto the other sensors described above 134, 384. In other embodiments, thelow-profile block 452 only includes a small portion of the femoralsurgical instrument 450. For example, the low-profile block 452 may besized to be big enough to only include the sensors 462.

Referring now to FIG. 20, another embodiment of a customizedpatient-specific acetabular surgical instrument 480 is shown. Theacetabular surgical instrument 480 includes a bone-attachment block 482and a shaft 484. The bone-attachment block 482 includes a bone-facingsurface (not shown), a sidewall 486, and a top wall 488. The bone-facingsurfacing of the bone-attachment block 482 has negative contours thatcorrespond to positive contours in the patient's coxal bone 136. Thebone-attachment block 482 is configured to be positioned in a specificlocation on the patient's coxal bone 136 near the acetabulum. Thebone-attachment block 482 also includes one or more sensors 490 todetermine the precise location of the bone-attachment block 482. Thesensors 490 are embodied similarly to the other sensors described above134, 384.

The shaft 484 extends from the top wall 488 of the bone-attachment block482 away from the coxal bone 136. The shaft 484 is configured to haveone or more surgical instruments 492 attach to the shaft 484. The one ormore surgical instruments 492 are supported and guided by the shaft 484during the orthopaedic surgical operation. The one or more surgicalinstruments 492 may include a reaming tool or an implant tool. The oneor more surgical instruments 492 may also include one or more sensors494. The one or more sensors 494 are configured to cooperate with thesensors 490 to assist the surgeon in following a pre-operative surgicalplan. For example, the sensors 490, 494 may determine when theacetabulum has been reamed to a predetermined depth. In someembodiments, the shaft 484 acts as an alignment guide. For example, theshaft 484 may cooperate with the surgical instruments 492 to ensure thatan acetabular component is positioned according to a predeterminedposition and orientation.

In other embodiments, the acetabular surgical instrument 480 may notinclude the shaft 484 shown in FIG. 20. In these embodiments, the one ormore sensors 490 cooperate with the sensors 494 positioned on thesurgical instruments 492, and other orthopaedic equipment, to validatethe use of the surgical instruments 492 during an orthopaedic surgicalprocedure.

Referring to FIG. 21, a method 500 for fabricating a customizedpatient-specific orthopaedic surgical instrument is illustrated. What ismeant herein by the term “customized patient-specific orthopaedicsurgical instrument” is a surgical tool for use by a surgeon inperforming an orthopaedic surgical procedure that is intended, andconfigured, for use on a particular patient. As such, it should beappreciated that, as used herein, the term “customized patient-specificorthopaedic surgical instrument” is distinct from standard, non-patientspecific orthopaedic surgical instruments that are intended for use on avariety of different patients. Additionally, it should be appreciatedthat, as used herein, the term “customized patient-specific orthopaedicsurgical instrument” is distinct from orthopaedic prostheses, whetherpatient-specific or generic, which are surgically implanted in the bodyof the patient. Rather, customized patient-specific orthopaedic surgicalinstruments are used by an orthopaedic surgeon to assist in theimplantation of orthopaedic components, such as acetabular cupprosthesis, femoral stem prosthesis, or other trialing components.

In some embodiments, the customized patient-specific orthopaedicsurgical instrument may be customized to the particular patient based onthe location at which the instrument is to be coupled to one or morebones of the patient, such as in an area of the patient's coxal boneproximate to the acetabulum. For example, in some embodiments, thecustomized patient-specific orthopaedic surgical instrument may includeone or more bone-contacting or facing surfaces having a negative contourthat matches the contour of a portion of the relevant bone of thepatient, which is discussed in more detail below in regard to FIGS. 2and 3. Illustratively, the customized patient-specific orthopaedicsurgical instrument may be embodied as a customized patient-specificacetabular surgical instrument or a customized patient-specific femoralsurgical instrument. The customized patient-specific acetabular surgicalinstrument is configured to be coupled to the patient's coxal bone in aunique location and position with respect to the patient's bony anatomy.That is, the negative contours of the bone-contacting surfaces areconfigured to receive a matching contour surface of the portion of thepatient's coxal bone. Similarly, the customized patient-specific femoralsurgical instrument is configured to be coupled to a patient's femurbone in a unique location and position with respect to the patient bonyanatomy. That is, the negative contours of the bone-contacting surfacesare configured to receive a matching contour surface of the portion ofthe patient's femur bone. With these customized patient-specificorthopaedic surgical instruments, the orthopaedic surgeon's guessworkand/or intra-operative decision-making with respect to the placement ofthe patient-specific acetabular orthopaedic surgical instrument arereduced. For example, the orthopaedic surgeon may not be required tolocate landmarks of the patient's bone to facilitate the placement ofthe patient-specific orthopaedic surgical instrument, which typicallyrequires some amount of estimation on part of the surgeon. Rather, theorthopaedic surgeon may simply couple the customized patient-specificorthopaedic surgical instrument to the patient's coxal bone or femurbone in the unique location. When so coupled, the patient-specificorthopaedic surgical instrument defines particular characteristics oforthopaedic prosthesis relative to the patient's bone. For example, thecustomized patient-specific acetabular surgical instrument defines aparticular degree of version and inclination angles relative to theacetabulum and the intended acetabular orthopaedic prosthesis. Inanother example, the customized patient-specific femoral surgicalinstrument defines a location of the offset of the femoral orthopaedicprosthesis relative to the femur.

As shown in FIG. 21, the method 500 includes steps 502 and 504, in whichan orthopaedic surgeon performs pre-operative planning of theorthopaedic surgical procedure to be performed on a patient. The steps502 and 504 may be performed in any order or contemporaneously with eachother. In step 502, a number of medical images of the patient'sacetabulum and the surrounding bony anatomy are generated. To do so, theorthopaedic surgeon or other healthcare provider may operate an imagingsystem to generate the medical images. The medical images may beembodied as any number and type of medical images capable of being usedto generate a three-dimensional rendered model of the patient'sacetabulum and surrounding bony anatomy. For example, the medical imagesmay be embodied as any number of computed tomography (CT) images,magnetic resonance imaging (MRI) images, or other three-dimensionalmedical images. Additionally, or alternatively, as discussed in moredetail below in regard to step 508, the medical images may be embodiedas a number of X-ray images or other two-dimensional images from which athree-dimensional rendered model of the area of the patient's coxal bone136 proximate to the acetabulum and the surrounding bony anatomy may begenerated.

In step 504, the orthopaedic surgeon may determine any additionalpre-operative constraint data. The constraint data may be based on theorthopaedic surgeon's preferences, preferences of the patient,anatomical aspects of the patient, guidelines established by thehealthcare facility, or the like. For example, the constraint data mayinclude the orthopaedic surgeon's preference for the amount ofinclination and version for the acetabular prosthesis, the implant depthof the acetabular prosthesis, the amount of the bone to ream, the sizerange of the orthopaedic implant, and/or the like. In some embodiments,the orthopaedic surgeon's preferences are saved as a surgeon's profile,which may be used as a default constraint values for further surgicalplans.

In step 506, the medical images and the constraint data, if any, aretransmitted or otherwise provided to an orthopaedic surgical instrumentvendor or manufacturer. The medical images and the constraint data maybe transmitted to the vendor via electronic means such as a network orthe like. After the vendor has received the medical images and theconstraint data, the vendor processes the images in step 508. Theorthopaedic surgical instrument vendor or manufacturer processes themedical images to facilitate the determination of the proper planes ofinclination and version, implant depth, implant sizing, and fabricationof the customized patient-specific orthopaedic surgical instrument, asdiscussed in more detail below.

In step 510, the vendor may convert or otherwise generatethree-dimensional images from the medical images. For example, inembodiments wherein the medical images are embodied as a number oftwo-dimensional images, the vendor may use a suitable computer algorithmto generate one or more three-dimensional images form the number oftwo-dimensional images. Additionally, in some embodiments, the medicalimages may be generated based on an established standard such as theDigital Imaging and Communications in Medicine (DICOM) standard. In suchembodiments, an edge-detection, thresholding, watershed, orshape-matching algorithm may be used to convert or reconstruct images toa format acceptable in a computer aided design application or otherimage processing application.

In step 512, the vendor may process the medical images, and/or theconverted/reconstructed images from step 510, to determine a number ofaspects related to the bony anatomy of the patient such as theanatomical axis of the patient's bones, the mechanical axis of thepatient's bone, other axes and various landmarks, and/or other aspectsof the patient's bony anatomy. To do so, the vendor may use any suitablealgorithm to process the images.

In step 514, the desired characteristics of the orthopaedic prosthesisare determined. For example, the desired inclination plane, the desiredversion plane, and the desired reaming depth for implantation of theacetabular orthopaedic prosthesis are determined. Each of thosevariables may be determined based on the type, size, and/or position ofthe acetabular orthopaedic prosthesis to be used during the orthopaedicsurgical procedure; the process images, such as specific landmarksidentified in the images; and the constraint data supplied by theorthopaedic surgeon in steps 504 and 506. The type and/or size of theacetabular orthopaedic prosthesis may be determined based on thepatient's anatomy and the constraint data. For example, the constraintdata may dictate the type, make, model, size, or other characteristic ofthe acetabular orthopaedic prosthesis. The selection of the acetabularorthopaedic prosthesis may also be modified based on the medical imagessuch that an acetabular orthopaedic prosthesis that is usable with theacetabulum of the patient and that matches the constraint data orpreferences of the orthopaedic surgeon is selected. Similarly, thedesired implant depth and the femoral head location for implantation ofthe femoral orthopaedic prosthesis may be determined. The process fordetermining the variables and characteristics for the femoralorthopaedic prosthesis is similarly embodied as the process describedabove regarding the acetabular orthopaedic prosthesis.

In addition to the type and size of the orthopaedic prosthesis, theplanned location and position of the orthopaedic prosthesis relative tothe patient's bony anatomy is determined. To do so, a digital templateof the orthopaedic prosthesis may be overlaid onto one or more of theprocessed medical images. The vendor may use any suitable algorithm todetermine a recommended location and orientation of the orthopaedicprosthesis (i.e., the digital template) with respect to the patient'sbone based on the processed medical images (e.g., landmarks of thepatient's acetabulum or the patient's femur defined in the images)and/or the constraint data. Additionally, any one or more other aspectsof the patient's bony anatomy may be used to determine the properpositioning of the digital template.

In some embodiments, the digital template along with surgical alignmentparameters may be presented to the orthopaedic surgeon for approval. Theapproval document may include the implant's planned characteristics. Forexample, the planned characteristics of the acetabular orthopaedicprosthesis may include planned inclination and version planes, theplanned depth to which the surgeon plans to ream, the orientation of thetransverse acetabular ligament and labrum, and other relevant landmarksof the patient's bony anatomy.

Regarding the acetabular surgical instrument, the proper inclination andversion planes for the acetabular orthopaedic prosthesis may then bedetermined based on the determined size, location, and orientation ofthe acetabular orthopaedic prosthesis. In addition, other aspects of thepatient's bony anatomy, as determined in step 512, may be used todetermine or adjust the planned inclination and version planes. Forexample, the determined mechanical axis, landmarks, and/or otherdetermined aspects of the relevant bones of the patient may be used todetermine the planned inclination and version planes.

In step 516, a model of the customized patient-specific orthopaedicsurgical instrument, which in an illustrative embodiment is a customizedpatient-specific acetabular orthopaedic surgical instrument, isgenerated. In some embodiments, the model is embodied as athree-dimensional rendering of the customized patient-specificorthopaedic surgical instrument. In other embodiments, the model may beembodied as a mock-up or fast prototype of the customizedpatient-specific orthopaedic surgical instrument. The patient-specificorthopaedic surgical instrument to be modeled and fabricated may bedetermined based on the acetabular orthopaedic surgical procedure to beperformed, the constraint data, and/or the type of orthopaedicprosthesis to be implanted in the patient.

The particular shape of the customized patient-specific orthopaedicsurgical instrument is determined based on the planned location andimplantation angles of the orthopaedic prosthesis relative to thepatient's bone. For example, the planned location of the customizedpatient-specific acetabular orthopaedic surgical instrument relative tothe patient's acetabulum may be selected based on, in part, the plannedinclination and version planes of the patient's acetabulum as determinedin step 514. In another example, the planned location of the customizedpatient specific femoral orthopaedic surgical instrument relative to thepatient's femur may be selected based on, in part, the planned positionof the femoral head of the femoral prosthesis. For example, in someembodiments, the customized patient-specific acetabular orthopaedicsurgical instrument is embodied as an acetabular reaming guide. In suchembodiments, the location of the acetabular reaming guide is selectedsuch that the acetabular reaming guide is usable to position theacetabular orthopaedic prosthesis at the planned inclination and versionplanes determined in step 514. Additionally, the planned location of theorthopaedic surgical instrument may be based on the identified landmarksof the patient's acetabulum identified in step 512.

In some embodiments, the particular shape or configuration of thecustomized patient-specific orthopaedic surgical instrument may bedetermined based on the planned location of the instrument relative tothe patient's bony anatomy. That is, the customized patient-specificorthopaedic surgical instrument may include a bone-contacting surfacehaving a negative contour that matches the corresponding contour of aportion of the bony anatomy of the patient such that the orthopaedicsurgical instrument may be coupled to the bony anatomy of the patient ina unique location, which corresponds to the pre-planned location for theinstrument. When the orthopaedic surgical instrument is coupled to thepatient's bony anatomy in the unique location, one or more guides (e.g.,cutting or drilling guide) of the orthopaedic surgical instrument may bealigned based on the orthopaedic surgical instrument, as discussedabove.

After the model of the customized patient-specific orthopaedic surgicalinstrument has been generated in step 516, the model is validated instep 518. The model may be validated by, for example, analyzing therendered model while coupled to the three-dimensional model of thepatient's anatomy to verify the correlation the planned characteristicsof the orthopaedic surgical instrument and orthopaedic prosthesis, suchas inclination and version planes and/or the like. Additionally, themodel may be validated by transmitting or otherwise providing the modelgenerated in step 516 to the orthopaedic surgeon for review. Forexample, in embodiments wherein the model is a three-dimensionalrendered model, the model along with the three-dimensional images of thepatient's bone may be transmitted to the surgeon for review. Inembodiments where the model is a physical prototype, the model may beshipped to the orthopaedic surgeon for validation.

After the model has been validated in step 518, the customizedpatient-specific orthopaedic surgical instrument is fabricated in step520. The customized patient-specific orthopaedic surgical instrument maybe fabricated using any suitable fabrication device and method.Additionally, the customized patient-specific orthopaedic instrument maybe formed from any suitable material such as a metallic material, aplastic material, or combination thereof depending on, for example, theintended use of the instrument. The fabricated customizedpatient-specific orthopaedic instrument is subsequently shipped orotherwise provided to the orthopaedic surgeon. The surgeon performs theorthopaedic surgical procedure in step 522 using the customizedpatient-specific orthopaedic surgical instrument. As discussed above,because the orthopaedic surgeon does not need to determine the properlocation of the orthopaedic surgical instrument intra-operatively, whichtypically requires some amount of estimation on part of the surgeon, theguesswork and/or intra-operative decision-making on part of theorthopaedic surgeon is reduced.

Variations in the bony anatomy of the patient may require more than onecustomized patient-specific acetabular orthopaedic surgical instrumentto be fabricated according to the method described herein. For example,the patient may require the implantation of two acetabular orthopaedicprostheses to replace both natural hips. As such, the surgeon may followthe method 500 of FIG. 21 to fabricate a different customizedpatient-specific acetabular orthopaedic surgical instrument for use inreplacing each natural hip. Each customized patient-specific acetabularorthopaedic surgical instrument defines a particular degree of versionangle and a particular degree of inclination angle relative to eachparticular acetabulum that is different due to the variation in the bonyanatomy of each hip.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such an illustration and descriptionis to be considered as exemplary and not restrictive in character, itbeing understood that only illustrative embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the method, apparatus, and system describedherein. It should be noted that alternative embodiments of the method,apparatus, and system of the present disclosure may not include all ofthe features described yet still benefit from at least some of theadvantages of such features. Those of ordinary skill in the art mayreadily devise their own implementations of the method, apparatus, andsystem that incorporate one or more of the features of the presentinvention and fall within the spirit and scope of the present disclosureas defined by the appended claims.

1. A method of using a system for facilitating implantation of a hipprosthesis, the method comprising: positioning a collar of a customizedpatient-specific femoral surgical instrument on a patient's femur bonesuch that (i) a negative contour defined in a bone-facing surface of thecollar receives a corresponding positive contour of the patient's femur,and (ii) a top surface of the collar defines a resection plane forresecting the patient's femur, advancing a resection tool along theresection plane surface of the collar to remove one or more portions ofthe patient's femur, positioning a femoral stem component in the femurbone, and aligning the femoral stem component with an alignment guidecoupled to the collar to position the femoral stem component in apredetermined position.
 2. The method of claim 1, further comprisingpositioning a customized patient-specific acetabular surgical instrumenton a patient's coxal bone such that a negative contour defined in thecustomized patient-specific acetabular surgical instrument receives acorresponding positive contour of the patient's coxal bone, positioningan acetabular cup component in the patient's coxal bone, and aligningthe acetabular cup component with an alignment guide coupled to the bodyto position the acetabular cup component in predetermined position. 3.The method of claim 2, further comprising determining the position ofthe customized patient-specific acetabular surgical instrument on thepatient's coxal bone using one or more sensors located in the customizedpatient-specific acetabular surgical instrument.
 4. The method of claim2, further comprising: forming an assembled hip joint prosthesis bypositioning a femoral head on the femoral stem component and insertingthe femoral head into a cavity of the acetabular cup component, anddetermining the position of the patient's coxal bone relative to thepatient's femur when the assembled hip joint prosthesis is implanted inthe patient using one or more sensors positioned in the customizedpatient-specific acetabular surgical instrument and one or more sensorspositioned in the customized patient-specific femoral surgicalinstrument.
 5. The method of claim 4, further comprising: attaching areaming guide housing and a reamer to the customized patient-specificacetabular surgical instrument, the reamer including one or more sensorspositioned thereon, reaming an acetabular of the patient to apredetermined depth, and determining how much bone has been removed fromthe acetabulum by comparing the data received from the sensors of thereamer to the data received from the sensors of the customizedpatient-specific acetabular surgical instrument.
 6. The method of claim1, further comprising determining the position of the customizedpatient-specific femoral surgical instrument on the patient's femurusing one or more sensors located in the collar.
 7. The method of claim1, further comprising positioning the alignment guide on the collar ofthe customized patient-specific femoral surgical instrument after thepatient's femur has been resected by the resection tool.
 8. The methodof claim 1, further comprising broaching an intramedullary canal of thepatient's femur using a reaming tool.
 9. A system for facilitatingimplantation of a hip prosthesis, the system comprising: a femoral stemcomponent defining a trunnion axis extending along a trunnion and a neckof the femoral stem component, and a customized patient-specific femoralsurgical instrument including: a collar sized to fit around a neck ofthe patient's femur, the collar having: (i) a bone-facing surface havinga customized patient-specific negative contour configured to receive acorresponding positive counter of the patient's femur, and (ii) topsurface defining a resection plane surface configured to guide asurgical instrument as the patient's femur is resected, and an alignmentguide coupled to the collar, the alignment guide defining a femoralalignment axis positioned to indicate a predetermined angle of thefemoral stem component.
 10. The system of claim 9, wherein the collarcomprises a first collar segment and a second collar segment connectedby a hinge, the hinge defining a hinge axis, and wherein the firstcollar segment and the second collar segment are configured to rotateabout the hinge axis to allow the customized patient-specific femoralsurgical instrument to advance onto the patient's femur.
 11. The systemclaim 9, wherein the alignment axis of the alignment guide indicates apredetermined offset of the femoral stem component from the patient'sfemur and indicates a predetermined angle of the femoral stem componentrelative to the patient's femur.
 12. The system of claim 9, wherein thecustomized patient-specific femoral surgical instrument includes one ormore sensors positioned in the collar and configured to determine aposition of the customized patient-specific femoral surgical instrumentrelative to the patient's femur, where the one or more sensors arepositioned in the customized patient-specific femoral surgicalinstrument based on a predetermined sensor position.